JP2008092778A - Motor with slowdown mechanism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve an yield by attaching a one-way clutch previously to the tip side of a worm thereby simplifying the manufacturing process of a motor with a slowdown mechanism. <P>SOLUTION: The inside diameter dimension of a tip side bearing 44 is set smaller than the inside diameter dimension of a central bearing 45, and the outside diameter dimension of a one-way clutch 33 is set equal to the inside diameter dimension of the tip side bearing 44. Consequently, the central bearing 45 and the tip side bearing 44 can be passed in a state that the one-way clutch 33 is attached previously to the tip side of a motor shaft 24, and the coupling work of the one-way clutch 33 and the tip side of the motor shaft 24 is not required to be performed in a gear case 40. Consequently, the manufacturing process of a power window motor 12 is simplified and the yield can be improved. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a motor with a speed reduction mechanism used as an actuator for a power window device or the like.

  In general, a motor with a speed reduction mechanism capable of obtaining a relatively large output is used as an actuator used in a power window device mounted on a vehicle such as an automobile. The motor with a speed reduction mechanism used in this power window device is required to prevent the window from being opened by an external force load. As a technique for this purpose, the speed reduction between the worm and the worm wheel constituting the speed reduction mechanism is required. It is known to use torque generated by the ratio, frictional force generated by the axial displacement of the motor shaft when an external force is applied to the worm wheel or when the worm wheel is driven to rotate.

  By the way, although the torque generated by the reduction ratio and the frictional force generated by the displacement of the motor shaft in the axial direction can prevent the window from being opened due to an external force load, it is normal for the window to be opened or closed by the driver. During the opening / closing operation, these torques and frictional forces become the driving resistance of the electric motor, and as a result, the motor efficiency is lowered. Therefore, in order to suppress such a decrease in motor efficiency, a motor with a speed reduction mechanism including a one-way clutch that operates or inactivates according to the displacement of the motor shaft in the axial direction and the rotation direction of the motor shaft, for example, It is described in Patent Document 1.

The motor with a speed reduction mechanism described in Patent Document 1 has an outer diameter that is larger than the inner diameter of the bearing between the bearing that rotatably supports the tip end of the motor shaft and the gear case in the axial direction of the motor shaft. A one-way clutch is mounted, and a decrease in motor efficiency is suppressed by the operation or non-operation of the one-way clutch.
JP 2005-110449 A

  However, according to the motor with a speed reduction mechanism described in Patent Document 1 described above, at the time of assembling, first, the bottom side of the bottomed worm accommodating portion in the gear case is positioned below, And then insert the one-way clutch from the bottom side of the worm housing, press-fit the bearing and fix it in place, then pass the front end of the motor shaft through the bearing, and the front end of the motor shaft at the center of the one-way clutch To connect both sides.

  Therefore, when the central axis of the one-way clutch that is inserted into the worm housing portion without being constrained on the outer peripheral side is inserted with a deviation from the central axis of the worm housing portion, the motor shaft is in a state guided by the bearing. It is necessary to check whether the front end side of the motor shaft and the one-way clutch are correctly connected, for example, by rotating the motor shaft, etc. The manufacturing process of the motor with a speed reduction mechanism was complicated and the yield was poor.

  An object of the present invention is to pre-assemble a one-way clutch on the tip side of a worm, simplifying the manufacturing process of a motor with a speed reduction mechanism, and improving the yield.

  The motor with a speed reduction mechanism according to the present invention includes an electric motor having a motor shaft integrally provided with a worm, a worm wheel that meshes with the worm and decelerates rotation of the motor shaft, and the worm attached to the electric motor. A motor with a speed reduction mechanism including a gear case that accommodates a wheel, the first bearing provided in the gear case and rotatably supporting the base end side of the worm of the motor shaft; and the gear case A second bearing that rotatably supports the front end side of the worm of the motor shaft, and a motor shaft that is assembled to the front end side of the motor shaft and is loaded with an external force from the worm wheel to the motor shaft. A one-way clutch that restricts relative rotation with the gear case, and the inner diameter of the second bearing is less than the inner diameter of the first bearing. And it sets to, and sets the outer diameter of the one-way clutch in the following inner diameter of the second bearing.

  The motor with a speed reduction mechanism according to the present invention is characterized in that the second bearing rotatably supports the one-way clutch.

  According to the present invention, the first bearing provided in the gear case and rotatably supporting the base end side of the worm of the motor shaft, and provided in the gear case, the tip end side of the motor shaft worm can be rotated freely. A second bearing to be supported, and a one-way clutch that is assembled on the front end side of the motor shaft and restricts relative rotation between the motor shaft and the gear case when an external force is applied from the worm wheel to the motor shaft. Is set to be equal to or smaller than the inner diameter of the first bearing, and the outer diameter of the one-way clutch is set to be equal to or smaller than the inner diameter of the second bearing. The bearing and the second bearing can be passed. Therefore, it is not necessary to connect the one-way clutch and the front end side of the motor shaft in the gear case, and the manufacturing process of the motor with the speed reduction mechanism can be simplified and the yield can be improved.

  According to the present invention, since the second bearing rotatably supports the one-way clutch, the distance between the second bearing and the gear case in the axial direction of the motor shaft can be shortened, and the motor with a speed reduction mechanism can be reduced in size. Can be achieved.

  Hereinafter, a first embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is an explanatory view for explaining a door of an automobile equipped with a power window device, FIG. 2 is a sectional view of a power window motor according to the first embodiment of the present invention, and FIG. 3 is a broken circle a portion of FIG. FIG. 4 is a partially enlarged sectional view, FIG. 4 is a front view showing a friction material attached to the power window motor, and FIG. 5 is a sectional view taken along line BB in FIG.

  As shown in FIG. 1, an elevating device 11 as a power window device is provided inside a door 10 of an automobile. The lifting device 11 includes a power window motor 12 as a motor with a speed reduction mechanism, a main arm 13 that swings and moves with the power window motor 12, a sub arm 14 that forms a link mechanism with the main arm 13, a main arm 13 and a sub arm. 14 has an end portion (upper end side in the figure) connected via a pulley (not shown) and the like, and has a window holder 15 that moves in the vertical direction in the figure while maintaining a horizontal state.

  The power window motor 12 is provided with a connector connecting portion 12a, and one end side of a connector wiring 16 as an electric wire is connected to the connector connecting portion 12a. The other end side of the connector wiring 16 is connected to, for example, an in-vehicle controller 17 installed inside a console box (not shown) in the vehicle. Then, when the driver opens or closes a power window switch (not shown) provided on the inside of the door 10, the power window motor 12 is driven to rotate in the forward direction or the reverse direction. The window 18 supported by the holder 15 opens and closes (lifts).

  As shown in FIG. 2, the power window motor 12 includes an electric motor 20 and a gear case 40 attached to the electric motor 20. The electric motor 20 includes a yoke 21 formed into a bottomed cylindrical shape by applying processing means such as press forming to a steel plate, and a pair of opposingly arranged radially inside the main body cylinder portion 21a of the yoke 21. A magnet (permanent magnet) 22 and a rotor (armature rotor) 23 that is rotatably provided inside each magnet 22 via a predetermined gap (air gap).

  A motor shaft (armature shaft) 24 is provided through the central axis of the rotor 23, and a base end side (right side in the drawing) of the motor shaft 24 is a base end attached to the stepped bottom 21 b of the yoke 21. The side bearing 25 is rotatably supported.

  A first steel ball 26 is rotatably mounted on the base end side of the motor shaft 24, and the first steel ball 26 has one side surface of a thrust plate 27 whose outer peripheral side is supported by a base end side bearing 25. (Left side in the figure). Thus, the rotational resistance of the motor shaft 24 is reduced by bringing the first steel ball 26 and the thrust plate 27 into point contact with each other.

  A substantially cylindrical elastic member 28 made of a synthetic resin such as hard rubber is provided on the other side surface (the right side surface in the figure) of the thrust plate 27. The motor shaft is elastically deformed in the axial direction of the elastic member 28. A predetermined amount of displacement in the axial direction of 24 is allowed, and rattling in the axial direction of the motor shaft 24 is prevented.

  A commutator 29 that is electrically connected to a coil 23 a wound around the rotor 23 is provided adjacent to the front end side (left side in the figure) of the rotor 23 in the motor shaft 24. The brush 41 provided in the gear case 40 is in sliding contact with a predetermined elastic force.

  A worm 30 is integrally formed on the tip side of the commutator 29 of the motor shaft 24, and the outer diameter dimension d1 of the worm 30 is smaller than the outer diameter dimension d2 of the motor shaft 24 (d1). <D2). Further, as shown in FIG. 3, a cylindrical portion 31 (d3 <d1) having an outer diameter d3 smaller than the outer diameter d1 of the worm 30 is integrally formed on the front end side of the worm 30 of the motor shaft 24. Further, a small-diameter cylindrical portion 32 having an outer diameter smaller than the outer diameter d3 of the cylindrical portion 31 is integrally formed on the distal end side. As described above, the worm 30, the cylindrical portion 31, and the small diameter cylindrical portion 32 constituting the motor shaft 24 are each formed to have a smaller diameter toward the tip end side of the motor shaft 24.

  A one-way clutch 33 is assembled to the small-diameter cylindrical portion 32 of the motor shaft 24. As shown in FIGS. 3 and 5, the one-way clutch 33 is formed in a bottomed cylindrical shape and has an outer diameter dimension of the cylindrical portion. The clutch housing 33a is set to have the same outer diameter dimension d3 as the outer diameter dimension d3 of 31. On the inner peripheral surface of the clutch housing 33a, clutch grooves 33b whose groove bottom surfaces are inclined so that the groove depth in the radial direction changes along the circumferential direction are formed at three locations at equal intervals in the circumferential direction. Has been.

  Between the clutch groove 33b and the small-diameter cylindrical portion 32 of the motor shaft 24 disposed at the center portion of the clutch housing 33a, substantially cylindrical clutch rollers 33c are provided at three locations corresponding to the respective clutch grooves 33b. ing. Each clutch roller 33c has a direction in which the distance between the outer peripheral surface of the small diameter cylindrical portion 32 and the inner peripheral surface of the clutch groove 33b is shortened by the elastic force of the coil spring 33d provided corresponding to each clutch roller 33c (see FIG. It is always pressed toward the counterclockwise direction.

  A second steel ball 33e is provided between the front end portion (left end side in FIG. 3) of the motor shaft 24 and the bottom portion of the clutch housing 33a. In addition, the rotational resistance of the motor shaft 24 is reduced.

  The gear case 40 is formed with a bottomed worm accommodating portion 42. Between the bottom portion in the axial direction of the worm accommodating portion 42 and one side surface (the left side surface in the drawing), for example, A substantially disc-shaped friction material 43 made of a heat resistant resin such as polyimide (PI) is mounted.

  As shown in FIG. 4, the friction material 43 has a main body 43a, and the main body 43a is formed with four notches 43b at equal intervals along the circumferential direction. By forming the notch 43b as described above, the elastic deformation of the main body 43a is facilitated, and the fixing work of the friction material 43 in the worm accommodating portion 42 can be easily performed. However, in the present embodiment, four cutouts 43b are provided at equal intervals in the main body 43a. For example, the number of the cutouts 43b may be arbitrarily adjusted according to the hardness of the material of the friction material 43. good. Further, the notch 43b of the main body 43a is omitted, the outer dimension of the main body 43a is set to be smaller than the inner diameter of the worm housing 42, and the friction material 43 is attached to the bottom of the worm housing 42 with an adhesive. You may make it fix with the adhesion | attachment means, such as.

  An annular protrusion 43c that protrudes toward the clutch housing 33a side and has a substantially semicircular cross section is integrally formed at the center of the main body 43a, and the top of the annular protrusion 43c contacts the clutch housing 33a. It is like that. The one-way clutch 33 is pressed against the friction material 43 by the elastic force of the elastic member 28 attached to the stepped bottom 21b of the yoke 21 in a state where the electric motor 20 is stopped, that is, in FIG. It is in the state shown.

  Here, the one-way clutch in the present invention is constituted by the clutch housing 33a, the clutch roller 33c, the second steel ball 33e, the small-diameter cylindrical portion 32, and the friction material 43.

  As shown in FIG. 2, the worm housing portion 42 of the gear case 40 has a first housing portion 42 a to which the friction material 43 is attached and a worm 30 having a larger diameter than the first housing portion 42 a from the bottom side. The second housing portion 42b and the third housing portion 42c having a diameter larger than that of the second housing portion.

  A distal end side bearing 44 as a second bearing in the present invention is press-fitted and fixed to the second accommodating portion 42 b side of the first accommodating portion 42 a, and the inner diameter dimension of the distal end side bearing 44 is that of the cylindrical portion 31. The same dimension d3 as the outer diameter dimension d3 is set. Therefore, the front end side bearing 44 can support the cylindrical portion 31 of the motor shaft 24 in a freely rotatable manner. Further, a central bearing 45 as a first bearing in the present invention is press-fitted and fixed to the third accommodating part 42 c of the worm accommodating part 42, and the inner diameter dimension of the central bearing 45 is that of the motor shaft 24. The same dimension d2 as the inner diameter dimension d2 is set. Therefore, the center bearing 45 can support the motor shaft 24 in a freely rotatable manner.

  The gear case 40 accommodates a worm wheel 46 that meshes with a worm 30 that is integrally formed with the motor shaft 24, and the front end side of an output shaft (not shown) attached to the central axis of the worm wheel 46 is It extends through the gear case 40 to the outside. A pinion gear (not shown) is attached to the distal end side of the output shaft, and the main arm 13 constituting the elevating device 11 (see FIG. 1) is caused to swing by the rotational drive of the pinion gear, The window 18 is raised and lowered.

  Here, the worm 30 and the worm wheel 46 constitute a speed reduction mechanism in the present invention. The speed reduction mechanism reduces the rotational speed of the output shaft of the worm wheel 46 with respect to the rotational speed of the worm 30, and The rotational torque is amplified, and therefore a relatively large output can be obtained while the motor is a relatively small motor that can be mounted inside the door 10 (see FIG. 1).

  A brush substrate 47 provided with a brush 41 is mounted on the electric motor 20 side of the gear case 40, that is, in the vicinity of the commutator 29 provided on the motor shaft 24, and a terminal (not shown) (not shown) One end side of the connection terminal) is connected. The other end of the terminal is led into a connector connecting portion 12a formed integrally with the gear case 40.

  Next, the operation of the power window motor 12 configured as described above will be described with reference to FIGS.

  When the driver opens the power window switch, an opening operation signal indicating that the power window switch has been opened is input to the in-vehicle controller 17, and the driving current (from the in-vehicle controller 17 to the power window motor 12 via the connector wiring 16 ( Open operation current). The supply of the opening operation current to the power window motor 12 causes the rotor 23 and the motor shaft 24 to rotate at high speed in the direction of arrow A in the drawing (forward rotation), and accordingly, the worm wheel 46 decelerates in the direction of arrow A in the drawing. Rotate. The window 18 (see FIG. 1) can be lowered (opened) at a predetermined speed by the rotational force of the worm wheel 46 having increased torque.

  At this time, a reaction force due to the weight or the like of the window 18 acts in the direction of arrow B in the figure of the worm wheel 46, whereby the motor shaft 24 is displaced in the direction of arrow C in the figure. As the motor shaft 24 is displaced in the direction of arrow C in the figure, the one-way clutch 33 assembled to the motor shaft 24 is separated from the friction material 43 and the motor shaft 24 compresses and deforms the elastic member 28.

  Here, as the motor shaft 24 rotates forward, the small-diameter cylindrical portion 32 is rotated in the direction of arrow A as shown in FIG. 5, and the small-diameter cylindrical portion 32 and the clutch housing 33a are integrated via each clutch roller 33c. The state, that is, the state where the one-way clutch 33 is effective is attempted. However, since the one-way clutch 33 is separated from the friction material 43 as described above, the motor shaft 24 can rotate without being restricted by the one-way clutch 33, and the window 18 is smoothly opened by the opening operation of the driver. Can be lowered.

  On the other hand, when the driver closes the power window switch, a closing operation signal indicating that the power window switch has been closed is input to the in-vehicle controller 17 and is driven from the in-vehicle controller 17 to the power window motor 12 via the connector wiring 16. A current (closed operation current) is supplied. The supply of the closing operation current to the power window motor 12 causes the rotor 23 and the motor shaft 24 to rotate at high speed (reverse rotation) in the direction of arrow B in the figure, and accordingly, the worm wheel 46 decelerates in the direction of arrow B in the figure. Rotate. Then, the window 18 can be raised (closed) at a predetermined speed by the torque of the worm wheel 46 having increased torque.

  At this time, a reaction force due to the weight of the window 18 acts on the worm wheel 46 in the direction of arrow A in the figure, and thereby the motor shaft 24 is displaced in the direction of arrow D in the figure. As the motor shaft 24 is displaced in the direction of arrow D in the figure, the clutch housing 33 a of the one-way clutch 33 assembled to the motor shaft 24 is pressed against the friction material 43 with a strong force.

  Here, with the reverse rotation of the motor shaft 24, the small diameter cylindrical portion 32 is rotated in the direction of arrow B as shown in FIG. 5, and each clutch roller 33c is separated from the small diameter cylindrical portion 32 and the clutch housing 33a, that is, a one-way clutch. 33 is in a released state (ineffective state). Therefore, the small-diameter cylindrical portion 32 can be rotated relative to the clutch housing 33a without substantial resistance, and the window 18 can be smoothly raised by the driver's closing operation.

  Further, when an external force is applied to the window 18 from the closed state of the window 18, that is, when the external force is applied in a direction forcibly opening the window 18 from outside the vehicle, the worm wheel 46 is rotated in the direction of arrow A in FIG. External force acts. Then, due to the engagement between the worm wheel 46 and the worm 30, the motor shaft 24 is displaced in the direction of arrow D in the figure, and the clutch housing 33 a of the one-way clutch 33 assembled to the motor shaft 24 has a strong force against the friction material 43. Is pressed.

  At this time, as shown in FIG. 5, the small-diameter cylindrical portion 32 is in a state where the one-way clutch 33 is effective in an attempt to rotate in the direction of arrow A in the figure, and under this state, the friction force between the clutch housing 33a and the friction material 43 causes The relative rotation of the motor shaft 24 with respect to the gear case 40 is restricted. As a result, it is possible to prevent the window 18 from being opened by an external force load when trying to forcefully open the window 18.

  As described above, when the window 18 is moved up and down when the motor is driven by the opening / closing operation of the driver, the window 18 can be moved up and down smoothly while the one-way clutch 33 is not effective. At the time (when the motor is stopped), it is possible to prevent the window 18 from being opened by the frictional force between the clutch housing 33a and the friction material 43 while the one-way clutch 33 is effective.

  Next, a method for assembling the power window motor 12 will be described with reference to FIGS. FIG. 6 is an explanatory diagram for explaining the gear case assembly process, FIG. 7 is an explanatory diagram for explaining the electric motor mounting process, and FIG. 8 is an explanatory diagram for explaining the procedure for inserting the motor shaft into the worm housing portion. .

  As shown by a one-dot chain line arrow in FIG. 6, first, the friction material 43, the front end side bearing 44, and the center bearing 45 are mounted in this order on the worm housing portion 42 of the gear case 40 to assemble the assembly of the gear case 40. Assemble (gear case assembly process). At this time, the friction material 43 is mounted on the bottom of the first housing portion 42a so that the annular protrusion 43c faces the opening side (right side in the drawing) of the gear case 40, and the front end side bearing 44 is the second of the first housing portion 42a. The central portion bearing 45 is press-fitted and attached to the opening side of the gear case 40 in the third accommodating portion 42c.

  Next, as shown by the one-dot chain line arrow in FIG. 7, the one-way clutch 33 is assembled in advance from the opening side of the gear case 40 after the gear case assembly process to the front end side of the motor shaft 24 in another assembly process. The assembly of the rotor 23 is mounted. After that, the assembly of the yoke 21, that is, the one in which the elastic member 28, the thrust plate 27, the base end side bearing 25 and the pair of magnets 22 are assembled in advance to the yoke 21 is mounted so as to cover the rotor 23. The gear case 40 and the electric motor 20 are fastened with the screw 50 (electric motor mounting step).

  In the electric motor mounting step, when the motor shaft 24 is inserted toward the worm housing portion 42, the shaft center of the worm housing portion 42 and the shaft center of the motor shaft 24 are shown in FIG. First, with respect to the central bearing 45 (inner diameter dimension d2) that rotatably supports the motor shaft 24, the one-way clutch 33 and the column part 31 (whichever is smaller than the inner diameter dimension) The outer diameter dimension d3) and the worm 30 (outer diameter dimension d1) are passed through.

  Thereafter, the motor shaft 24 is continuously inserted into the worm housing portion 42, and the one-way clutch 33 is passed through the tip side bearing 44 (outer diameter dimension d3), and one side of the one-way clutch 33 (left side in the figure). Surface) is brought into contact with the annular protrusion 43c of the friction material 43. As a result, the cylindrical portion 31 of the motor shaft 24 is rotatably supported by the front end side bearing 44, and the motor shaft 24 is rotatably supported by the center portion bearing 45.

  Then, following the electric motor mounting step, the pair of magnets 22 are magnetized by a magnetizing power supply device (not shown), and then the worm wheel 46 (see FIG. 2) is assembled to the gear case 40 so as to mesh with the worm 30 and the gear case 40 On the other hand, the assembly of the power window motor 12 is completed by attaching a case cover (not shown).

  As described above in detail, according to the power window motor 12 according to the first embodiment of the present invention, the center provided in the gear case 40 and rotatably supports the base end side of the worm 30 of the motor shaft 24. A bearing 45, a tip end bearing 44 provided in the gear case 40 and rotatably supporting the cylindrical portion 31 on the tip end side of the worm 30 of the motor shaft 24, and a worm wheel assembled to the tip end side of the motor shaft 24. And a one-way clutch 33 that restricts relative rotation between the motor shaft 24 and the gear case 40 when an external force is applied from the motor 46 to the motor shaft 24, and the inner diameter dimension d3 of the front end side bearing 44 is made smaller than the inner diameter dimension d2 of the central bearing 45. Since the outer diameter dimension d3 of the one-way clutch 33 is set to be equal to or smaller than the inner diameter dimension d3 of the distal end side bearing 44, the distal end of the motor shaft 24 is set. In pre-assembled condition original one-way clutch 33 can be passed through a central portion bearing 45 and the distal end side bearing 44.

  Therefore, it is not necessary to connect the one-way clutch 33 and the front end side of the motor shaft 24 in the gear case 40 as before, and the manufacturing process of the power window motor 12 can be simplified and the yield can be improved. .

  The one-way clutch 33 can be mounted on the motor shaft 24 without dropping from the motor shaft 24 due to the elastic force of the coil spring 33d, so that the bottom side of the worm housing portion of the gear case is positioned downward as before. Thus, it is not necessary to assemble the electric motor to the gear case, and as shown in FIGS. 7 and 8, the gear case 40 and the electric motor 20 can be assembled in a horizontal state or the like. Therefore, the layout of the production line for the power window motor 12 can be improved.

  Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 9 shows a partially enlarged cross-sectional view corresponding to the broken-line circle a in FIG. 2 in the second embodiment. In addition, about the part which has the same function as the said 1st Embodiment, the same symbol is attached | subjected and the detailed description is abbreviate | omitted.

  As shown in FIG. 9, the power window motor 60 according to the second embodiment omits the cylindrical portion 31 of the motor shaft 24 that is rotatably supported by the front end side bearing 44 as compared with the first embodiment. The difference is that the one-way clutch 33 is rotatably supported by the front end side bearing 44.

  Also in the power window motor 60 according to the second embodiment configured as described above, the same operational effects as those of the power window motor 12 in the first embodiment described above can be obtained. In addition, according to the power window motor 60 according to the second embodiment, the more distal end side of the motor shaft 24 is rotatably supported by the distal end side bearing 44, so that the motor shaft 24 generated when the motor shaft 24 rotates. The vibration on the front end side can be more effectively suppressed, the generation of abnormal noise can be suppressed, the life of the one-way clutch 33 can be extended, and the like. Moreover, since the distance with respect to the axial direction between the friction material 43 and the front end side bearing 44 can be shortened, as shown by the dashed-two dotted line in a figure, size reduction of the power window motor 60 can be achieved.

  It goes without saying that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. For example, in each of the above-described embodiments, the inner diameter dimension d3 of the front end side bearing 44 is set to be smaller than the inner diameter dimension d2 of the central bearing 45. However, the present invention is not limited to this, and the worm 30 The inner diameter dimension of the tip side bearing 44 may be set to the same dimension as the inner diameter dimension of the central bearing 45 as long as the outer diameter dimension d1 is larger than the outer diameter dimension d1. In this case, the front end side bearing and the center bearing can be shared, and the manufacturing cost can be reduced.

  Moreover, in the said 1st Embodiment, the outer diameter dimension d3 of the cylindrical part 31 rotatably supported by the front end side bearing 44 and the outer diameter dimension d3 of the one-way clutch 33 are set to the same dimension. However, the present invention is not limited to this, and the outer diameter dimension of the one-way clutch 33 may be set to be smaller than the outer diameter dimension of the cylindrical portion 31. In this case, since the passage of the one-way clutch 33 with respect to the front end side bearing 44 can be facilitated, the assembling property of the power window motor 12 can be further improved.

  Further, in each of the above embodiments, the motor with a speed reduction mechanism is a power window motor having a function of preventing the window from being opened by an external force load. However, the present invention is not limited to this. However, the present invention can also be applied to other motors with a speed reduction mechanism used in, for example, a sunroof device or the like that requires the same function.

  Moreover, in each said embodiment, although the thing with the motor with a reduction mechanism with a brush provided with the brush 41 was shown as a motor with a reduction mechanism, this invention is not limited to this, For example, with a reduction mechanism It can also be applied to a brushless motor or the like.

It is explanatory drawing explaining the door of the motor vehicle provided with the power window apparatus. It is sectional drawing of the power window motor in 1st Embodiment of this invention. It is a partial expanded sectional view of the broken-line circle | round | yen part of FIG. It is a front view which shows the friction material with which a power window motor is mounted | worn. It is sectional drawing which follows the BB line of FIG. It is explanatory drawing explaining a gear case assembly process. It is explanatory drawing explaining an electric motor mounting process. It is explanatory drawing explaining the insertion procedure of the motor shaft to a worm accommodating part. It is a partial expanded sectional view corresponding to the broken-line circle | round | yen part of FIG. 2 in 2nd Embodiment.

Explanation of symbols

10 Door 11 Lifting device (Power window device)
12, 60 Power window motor (motor with reduction mechanism)
12a Connector connection part 13 Main arm 14 Sub arm 15 Window holder 16 Connector wiring 17 Car-mounted controller 18 Window 20 Electric motor (motor with reduction mechanism)
21 Yoke 21a Body cylinder portion 21b Stepped bottom portion 22 Magnet 23 Rotor 23a Coil 24 Motor shaft 25 Base end side bearing 26 First steel ball 27 Thrust plate 28 Elastic member 29 Commutator 30 Worm (motor shaft, speed reduction mechanism)
31 Cylindrical part (motor shaft)
32 Small diameter cylindrical part (motor shaft, one-way clutch)
33 One-way clutch 33a Clutch housing (one-way clutch)
33b Clutch groove 33c Clutch roller (one-way clutch)
33d Coil spring (one-way clutch)
33e 2nd steel ball (one-way clutch)
40 Gear case (motor with reduction mechanism)
41 Brush 42 Worm housing portion 42a First housing portion 42b Second housing portion 42c Third housing portion 43 Friction material (one-way clutch)
43a body part 43b notch part 43c annular projection 44 tip side bearing (second bearing)
45 Center bearing (first bearing)
46 Worm wheel (deceleration mechanism)
47 Brush substrate 50 Screw

Claims (2)

An electric motor having a motor shaft integrally provided with a worm, a worm wheel that meshes with the worm and decelerates rotation of the motor shaft, and a gear case that is attached to the electric motor and accommodates the worm wheel. A motor with a speed reduction mechanism,
A first bearing provided in the gear case and rotatably supporting a base end side of the worm of the motor shaft;
A second bearing provided in the gear case and rotatably supporting a tip end side of the worm of the motor shaft;
A one-way clutch that is assembled to the front end side of the motor shaft and restricts relative rotation between the motor shaft and the gear case when an external force is applied from the worm wheel to the motor shaft;
A motor with a speed reduction mechanism, wherein an inner diameter dimension of the second bearing is set to be equal to or smaller than an inner diameter dimension of the first bearing, and an outer diameter dimension of the one-way clutch is set to be equal to or smaller than an inner diameter dimension of the second bearing.   2. The motor with a speed reduction mechanism according to claim 1, wherein the second bearing rotatably supports the one-way clutch.

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